Water activated gas buoyancy device



March 30, 1965 G. DE VRIES WATER ACTIVATED GAS BUOYANCY DEVICE 2Sheets-Sheet 1 Filed Dec. 9, 1963 INVENTOR. GERRIT DE VRIES 7/4.ATTORNEY.

United States Patent C) i WATER ACTIVATED GAS BUOYANCY DEVICE Geri-it DeVries, Altadena, Califi, asslgnor to the United States of America asrepresented by the Secretary of the Navy Filed Dec. 9, 1963, Ser. No.329,323

' 9 Claims. (Cl. 11420) (Granted under Title 35, US. Code (1952), see.266) The invention described herein may be manufactured and used by orfor the Government of the United States of America for governmentalpurposes without the payment of any royalties thereon or therefor.

This invention relates to apparatus for recovering a negatively buoyanttorpedo, subsequent to the completion of an exercise or test run, andfrom a predetermined depth in the sea which depth is above the floor ofthe sea.

It is common practice to recover torpedoes which have sunken to thefloor of the sea after completion of an exercise or test run, exemplaryof which is the patent application of Ernest N. Oeland, Jr and JohnYoung, Jr., Serial No. 32,984, filed April 19, 1963, now Patent No.3,123,842, and the Dayer patent referred to in such application. Indevices of this type a float is released from the sunken torpedo, whichrises to the surface, laying a line between the torpedo and float whichlatter may be located 011 the surface of the sea after which suitablehoisting apparatus maybe employed to follow the line to the torpedo,latch to it, and permit raising the torpedo by a surface winch or thelike. While such devices enable recovery of a torpedo beyond diverdepths they suffer the disadvantage that if the floor of the sea is atgreat depth sufficient cordage cannot be carried unless the device is ofexcessive bulk. Additionally, the time required for the torpedo to sinkto the floor of the sea from a predetermined depth and then be raised tosuch depth represents a considerable loss in time in the recoveryoperation. Another type of recovery apparatus, probably more analogousto the present invention, is exemplified by the patent to Newburn et al.2,949,877 wherein flotation bags are inflated at a desired depth undercontrol of a depth responsive device, such as a hydrostat, a suitablepropellant being provided which generates hot gas for inflating thebags. This gas must be cooled, however, before being delivered to thebags, necessitating bulky cooling apparatus. Also, the balancing ofinternal bag pressure to the ambient sea pressure depends on theoperation of a pressure release valve, the failure of which could causebursting of the bags and loss of a torpedo. Additionally, at the time ofinflation of the bags, the descending velocity of the torpedo may be sogreat that shock forces may cause failure of the apparatus.

One of the objects of this invention is to provide flotation apparatusfor anegatively buoyant torpedo which generates gas within an inflatablebag which is open to the sea.

Another object is to check the speed of a topedo before inflation of thebag.

Another object is to withdraw the bag from a cavity within a torpedo byutilizing the drag and buoyancy forces of a cover closing one end of thecavity.

Further objects are to provide torpedo recovery apparatus which isextremely simple in construction, economical of manufacture and has aminimum of operative mechanical parts subjected to malfunction.

Other objects, advantages and salient features will become more apparentfrom a consideration of the description to follow, the appended claims,and the accompanying drawing in which:

FIG. 1 is a side elevation of a torpedo embodying the subject of theinvention;

ice

FIG. 2 is a longitudinal central vertical section through a portion ofFIG. 1;

FIG. 3 is an enlarged detail of the portion of FIG. 2 indicated by arrow3; and

FIG. 4 is an enlarged detail of the portion of FIG. 2 indicated by arrow4 in a different position of parts.

Referring now to the drawing, any conventional negatively buoyanttorpedo 10 may be provided with a recovery section 12, forming thesubject of the invention, connected intermediate of the ends of thetorpedo hull by conventional torpedo hull joints 13, 13A. In general,such recovery section will replace the torpedo warhead section when itis desired to exercise the torpedo or otherwise conduct test runs of thetorpedo.

As shown in FIG. 2, hull section 12 is provided with a frusto-conicalcavity 14 extending radially of the hull, its lower ends being closed bya lower cover 16 and its upper end closed by an upper cover 18. Lowercover 16 is secured to the section by a hinge 20 which permits it toswing to the position shown in dotted lines or to the lowermost positionof the torpedo, as shown in FIG. 1. A cord 22, having one end secured toan eye 24 on the cover, and its other end 26 secured to the hull sectionserves as a stop to limit rearward pivotal movement.

Upper cover 18, formed of buoyant plastic or other buoyant material, isprovided with a tapered edge portion 28 which engages a correspondingedge 30 which permits the cover to pivot about a transverse axis passingthrough their abutment. A projection 32 on the cover engages within arecess 34, locking the cover against radial outward movement butpermitting the pivotal movement and also bodily release of the cover aswill subsequently appear.

The forward edge of lower cover 16 is locked in the position shown inFIG. 2 by a latch pin or detent 36, forming a part of a piston 38, urgedin one direction by a spring 40 which maintains an end of the projectionwithin an aperture 42 in the cover. A shear wire 44 extends through aportion of the section and the projection to prevent movement of thepiston by the pressure of the sea water until the torpedo descends to adepth suflicient to move the piston and shear the wire. As will beapparent from the drawing the upper lid is locked in the same manner.The upper piston 38A, however, is sealed against entry of sea water byan O-ring 46 and the pressure to operate it is communicated through atube 48. When piston 38 moves to the left, as shown in FIG. 4, touncover aperture 50, sea water enters tube 48 and actuates piston 38A.As will be apparent, this provides a time elay between operation of thepistons, piston 38 operating first to release lower cover 16 and a shorttime later piston 38A operating to release upper cover 18.

To initiate opening of the covers, a tube 52 is provided which containsa pair of springs 54, 54A, both engaging a common abutment 56, whichurge plungers 58, 58A radially outwardly, the outer ends of the plungersengaging the respective lower and upper covers.

A collapsed bag are substantially fills cavity 14, the bag beingconstructed of rubber zed fabric or the like, and having a mouth 62 atone end closed by a removable circular plug 64, which, as best shown inFIG. 3, frictionally fits within an annular metal collar or ring 66;secured to a ring 68 by angularly spaced screws 70, the edge of the bagaround its mouth being clamped between the collar and ring. An O-iing72, carried by the plug, seals against entry of water into the bag. Apop-out circular screen 74, the edge of which is disposed within acircular groove 76 in collar 66, permits entry of water into the bagwhen the plug 64 is removed and also retains a water reactantmaterial-78 within the bag.

Cover 18 is connected to section 12 by a flexible cord 80, one end 82 ofwhich is secured to pin 84, aifixed to the 3 section. As best shown inFIG. 2, cord 30 extends around the sides and bottom of the bag, itsother end terminating in a bridle 86, consisting of several lines 88.

Bag 60 is similarly connected to section 12 by a cord 90 having one endsecured to pin 84, its other end terminating in a bridle 92, the bridlelines being secured to collar 66 at angularly spaced points, as bestshown in FIG. 2.

Another cord or lanyard 96 (FIG. 2) has one end secured to a pulloutvent valve 98 in plug 64, its other being secured to pin 84. Plug 64 isconnected to a like bridle 100, its cord also being connected to pin 84.This cord is shorter than cord 96 so that it wiil become taut beforecord 90 for a purpose to be subsequently described.

In the operation of the apparatus, and first with reference to FIG. 1,it will be assumed that negatively buoyant torpedo is moving along ahorizontal course at some predetermined depth in the sea and that itspropulsion apparatus has ceased operation either by intentionalprogramming or by consumption of its fuel supply or other source ofenergy. As illustrated, the torpedo goes into a dive and, when itreaches a predetermined depth, water pressure acting on piston 38 shearswire 44 and the piston moves to the position shown in FIG. 4, unlatchinglower cover 16. Spring 54, acting on plunger 58, swings the cover towardopen position and the water slipstream acts on the inner face of thecover moving it to full open position. It now acts as a rudder to turnthe torpedo toward a horizontal position as best shown in the lowerposition of FIG. 1 which attitude of the torpedo is more favorable forinitiating operation of the recovery apparatus. Some time during thisturn, as determined by the time delay between operation of piston 38 andpiston 33A, the latter similarly shears its shear wire and upper spring54 initiates opening of the upper cover. As it opens, it is likewisecaught in the slip stream and, due to its buoyancy and drag, movesupwardly relative to the torpedo. During this movement, and since itsattaching cord extends around the bag, the bag is withdrawn from thecavity as the cord tensions. When the bag is withdrawn, it also iscaught in the slip stream and is dragged with its mouth facing thedirection of movement. As previously set forth, the cord connected tobridle 100 becomes taut before cord 90 which withdraws plug 64 from themouth of the bag. Water now rushes into the bag filling it. As the waterreacts with material 78, gas is formed which displaces the water,forcing it out of the mouth of the bag, the pressure within the bagalways remaining only slightly above ambient pressure. As the water isforced out, the bag increases in buoyancy and when the increase issufiicient to overcome the negative buoyancy of the torpedo, the latteris lifted to the surface of the water where it may be recovered.

A water reactant material which has been found satisfactory is lithiumhydride in granular form with partial size of the order of 40 mesh. Whenthe mouth plug is removed, water rapidly enters the bag carrying thematerial with it and interspersing it throughout the mass of waterwithin the bag. Rapid reaction takes place forming hydrogen underpressure which forces the water out of the bag. When substantially allof the water has been displaced by the gas any remaining lithium hydrideand the insoluble products of reaction collect on the screen. In eventthe screen should completely clog, pressure will increase in the bag andforce the screen out of the mouth of the bag thus preventing furtherrise of pressure which might rupture the bag. Another safety feature isthe vent valve in the mouth plug. Since the water reactant material isgranular, the pressure transmitted to the inside of the bag by ambientwater compressing the outside of the bag may be somewhat less thanambient pressure. The force required to remove the plug is thus equal tothe product of the difierence in pressure and the area of the plug.Since this force might be greater than the force applied to bridle 100it is apparent that the plug would not be removed from the mouth of thebag. By removing vent valve 98, however, water may enter through theaperture which is formerly closed, equalizing the pressure within thebag to ambient pressure. It has been found, also, that the pressurewithin the bag, prior to removing the plug, can be made more nearlyequal to ambient pressure by filling the interstices between the lithiumhydride with lubricating oil thus forming a more solid mass upon whichthe bag presses. This also retards the reaction of the lithium hydride,permitting the exothermic heat of reaction to be dissipated into ambientwater, preventing burning of the bag. The use of vent plug 98 or the oilreferred to are optional features which may or may not be requireddepending upon recovery requirements of the particular torpedo. Forexample, if recovery must be initiated rapidly to prevent descent of thetorpedo to a depth at which its hull might be crushed by ambient water,then a rapid rate of reaction of the lithium hydride would normally berequired. If the depth at which recovery is initiated is not critical,however, then the reaction time could usually be increased. As will beapparent, the time for filling the bag with gas can thus be preselectedby choice of particle size of the lithium hydride, the smaller the sizethe more rapid the reaction, and by choice of an inhibitor which willcontrol reaction rate.

In some instances it may be desirable to increase the drag of the bag toprovide a greater pulling force on the removable plug which closes themouth of the bag. For this purpose a parachute may be employed (notshown), the shroud lines of which are connected to collar 66. The dragof the bag and parachute will open the parachute producing additionaldrag. The length of the shroud lines is preferably such that theparachute canopy will be disposed rearwardly of the bag when theparachute opens.

Obviously many modifications and variations of the present invention arepossible in the light of the above teachings. It is therefore to beunderstood that within the scope of the appended claims the inventionmay be practiced otherwise than as specifically described.

What is claimed is:

1. Apparatus of the type for recovering a negative buoyant sinkingtorpedo, which apparatus becomes operative when the torpedo has sunk toa predetermined depth in the sea and above the floor of same,comprising;

(a) a transversely extending cavity within the torpedo having a firstopening at one side thereof,

(b) a buoyant releasable closure closing said opening,

(0) an inflatable collapsed flexible bag disposed within said cavityhaving a mouth at one end of same,

(d) a removable plug closing said mouth,

(e) a water reactant material disposed within said bag,

adapted to produce gas,

(f) a first cord extending partly around said bag having one end aflixedto the torpedo and its other end atfixed to said buoyant closure,

(g) a second cord having one end afi'ixed to the torpedo and its otherend to the bag adapted to drag the bag through the water with the mouthdisposed in a position relative to the water such that water may enterthe mouth and fill the bag,

(It) a removable plug closing the mouth of the bag having a lanyardconnecting same to the torpedo adapted to be tensioned and remove theplug after the bag is withdrawn from said cavity,

(i) and release means for releasing said buoyant closure when thetorpedo has sunk to a predetermined depth,

(j) the construction and arrangement being such that when said releasemeans becomes operative said buoyant closure is bodily released from thetorpedo effecting withdraw of the bag from the cavity, the plug isremoved from the mouth of the bag, water enters the bag filling same andreacting with the water reactant material, producing gas which expelsthe water from the bag, producing sufficient buoyancy such that the bagmay raise the torpedo to the surface of the water.

2. Apparatus in accordance with claim 1 wherein,

(k) said cavity is provided with a second opening at the opposite sideof the torpedo,

(l) a swingable closure closing the second opening, said swingableclosure adapted to swing to a limit position to form a rudder to turnthe torpedo about a transverse axis with said first opening facing in anupward direction.

3. Apparatus in accordance with claim 2 including time delay means forpermitting said swingable closure to first open and turn the torpedo andthereafter cause release of said buoyant releasable closure.

4. Apparatus in accordance with claim 3 wherein said time delay meanscomprises first and second movable piston actuators restrained againstmovement by a shear wire associated with each, the first piston actuatorbeing subjected to sea pressure and operatively connected to saidswingable closure by a detent, the second piston actuator beingoperatively connected to said buoyant releas able closure by a likedetent, and a conduit communicating the actuators only after the firstactuator has sheared its shear wire and moved to a limit position,whereby a time delay is effected between operation of the actuators.

5. Apparatus in accordance with claim 2 including a first spring forinitiating opening of said swingable closure to a position in thetorpedo slip stream, the slip stream being effective to further open itto its limit position, and a second spring for initiating opening ofsaid buoyant cover, the buoyant cover thereafter adapted to disengagefrom the torpedo due to its buoyancy and drag in the slip stream.

6. Apparatus in accordance with claim 1 including a screen disposedacross the mouth of the bag and releasably secured to same in a mannersuch that the screen may be ejected from the mouth in event ofsubstantially complete clogging by solid products of reaction, wherebygas pressure within the bag cannot increase sufiiciently to rupture thebag.

7. Apparatus in accordance with claim 1 including a removable vent valvein said plug, and a lanyard connecting said vent valve with the torpedoadapted to remove the vent valve when the lanyard is tensioned, wherebywater may enter the bag through the vent valve and raise the pressuretherein to at least the ambient pressure of the sea, to therebyfacilitate removal of said removable plug.

8. Apparatus for recovering a negatively buoyant sinking body, whichapparatus becomes operative when the body has sunk to a predetermineddepth in the sea and above the floor of same, comprising;

(a) an inflatable collapsed flexible bag having a mouth at one end ofsame,

(b) a removable plug closing said mouth,

(0) a water reactant material disposed within said bag adapted toproduce gas,

(d) a cord of fixed length having one end affixed to the body and itsother end to the mouth of the bag adapted to drag the bag through thewater in constant spaced relation to the body, with the mouth disposedin the direction in which the bag is being dragged so that water mayenter the mouth and fill the bag,

(e) transfer means for transferring the collapsed bag from the body intothe slipstream, when desired, to be dragged by its affixed cord,

(f) and means for removing said plug,

(g) the construction and arrangement being such that when the plug isremoved from the mouth of the bag, water enters the bag filling same andreacting with the water reactant material, producing gas which expelsthe Water from the bag, producing sufficient buoyancy such that the bagmay raise the body to the surface of the water gas being expelledthrough said mouth as the bag and body rise to the surface.

9. Apparatus for recovering a negatively buoyant sinking body, whichapparatus becomes operative when the body has sunk to a predetermineddepth in the sea and above the floor of same, comprising;

(a) an inflatable collapsed flexible bag having a mouth at one end ofsame,

(b) a removable plug closing said mouth,

(c) a water reactant material disposed within said bag adapted toproduce gas,

(d) a cord having one end affixed to the body and its other end to thebag adapted to drag the bag through the water, with the mouth disposedin a position relative to the water such that Water may enter the mouthand fill the bag,

(e) transfer means for transferring the collapsed bag into theslipstream, when desired, to be dragged by its affixed cord,

(7) means for removing said plug,

(g) the construction and arrangement being such that when the plug isremoved from the mouth of the bag, water enters the bag filling same andreacting with the water reactant material, producing gas which expelsthe water from the bag, producing suflicient buoyancy such that the bagmay raise the body to the surface of the water.

(h) a cavity within said body having an opening disposed at the top ofsame, when the body is moving horizontally, said cavity containing thebag, and

(i) a rudder adapted to be actuated prior to operation of the transfermeans for turning the body about a horizontal axis to dispose saidcavity at the top of the body, in event the body is sinking with itslongitudinal axis disposed in a generally vertical position, whereby thebag is transferred to the slipstream during an optimum orientation ofthe body.

References Cited by the Examiner FOREIGN PATENTS 372,923 4/07 France.

BENJAMIN A. BORCHELT, Primary Examiner.

FRED C. MATTERN, JR., Examiner.

1. APPARATUS OF THE TYPE FOR RECOVERING A NEGATIVE BUOYANT SINKINGTORPEDO, WHICH APPARATUS BECOMES OPERATIVE WHEN THE TORPEDO HAS SUNK TOA PREDETERMINED DEPTH IN THE SEA AND ABOVE THE FLOOR OF SAID,COMPRISING; (A) A TRANSVERSELY EXTENDING CAVITY WITHIN THE TORPEDOHAVING A FIRST OPENING AT ONE SIDE THEREOF, (B) A BUOYANT RELEASABLECLOSURE CLOSING SAID OPENING, (C) AN INFLATABLE COLLAPSED FLEXIBLE BAGDISPOSED WITHIN SAID CAVITY HAVING A MOUTH AT ONE END OF SAME, (D) AREMOVABLE PLUG CLOSING SAID MOUTH, (E) A WATER REACTANT MATERIALDISPOSED WITHIN SAID BAG, ADAPTED TO PRODUCE GAS, (F) A FIRST CORDEXTENDING PARTLY AROUND SAID BAG HAVING ONE END AFFIXED TO THE TORPEDOAND ITS OTHER END AFFIXED TO SAID BUOYANT CLOSURE, (G) A SECOND CORDHAVING ONE END AFFIXED TO THE TORPEDO AND ITS OTHER END OF THE BADADAPTED TO DRAG THE BAG THROUGH THE WATER WITH THE MOUTH DISPOSED IN APOSITION RELATIVE TO THE WATER SUCH THAT WATER MAY ENTER THE MOUTH ANDFILLED THE BAG, (H) A REMOVABLE PLUG CLOSING THE MOUTH OF THE BAG HAVINGA LANYARD CONNECTING SAME TO THE TORPEDO ADAPTED TO BE TENSIONED ANDREMOVE THE PLUG AFTER THE BAG IS WITHDRAWN FROM SAID CAVITY, (I) ANDRELEASE MEANS FOR RELEASING SAID BUOYANT CLOSURE WHEN THE TORPEDO HASSUNK TO A PREDETERMINED DEPTH, (J) THE CONSTRUCTION AND ARRANGEMENTBEING SUCH THAT WHEN SAID RELEASE MEANS BECOMES OPERATIVE SAID BUOYANTCLOSURE IS BODILY RELEASED FROM THE TORPEDO EFFECTING WITHDRAW OF THEBAG FROM THE CAVITY, THE PLUG IS REMOVED FROM THE MOUTH OF THE BAG,WATER ENTERS THE BAG FILLING SAME AND REACTING WITH THE WATER REACTANTMATERIAL, PRODUCING GAS WHICH EXPELS THE WATER FROM THE BAG, PRODUCINGSUFFICIENT BUOYANCY SUCH THAT THE BAG MAY RAISE THE TORPEDO TO THESUFACE OF THE WATER.